Administration of platelets is a strategy for medical care of patients with thrombocytopenia, e.g., caused by bone marrow dysfunctions or chemotherapy treatments. Platelets are also administered prior to stem cell transplantation. Donated platelets are concentrated and typically stored at 22-24° C. under continuous gentle agitation in bags permeable to oxygen, in order to promote aerobic metabolism instead of glycolysis. However, platelets are not used after the fifth day of storage because of platelet storage lesions and an increased risk of bacterial and viral contamination. Platelets stored at temperatures below 15° C. may slow these undesirable processes; unfortunately, in practice, after administration, they are rapidly cleared from the bloodstream of the recipients. Thus, there is a need to identify improved methods of storing platelets.
Platelet membrane glycoproteins are surface glycoproteins found on platelets (thrombocytes) which play an important role in hemostasis. Glycoprotein Ib-IX-V complex (GPIb-IX-V) contains the subunits: GPIb alpha (GPIbα), GPIb beta (GPIbβ), GPV and GPIX. GPIba subunit bears the binding site for von Willebrand factor (vWF). The binding between GPIba and vWF mediates the capture of platelets to the injured vascular wall. A deficiency in glycoprotein Ib-IX-V complex leads to Bernard-Soulier syndrome, an inherited disease with symptoms of excessive bleeding.
Glycoprotein Ibα (GPIbα) is abundantly expressed on the platelet surface. In addition to its function in mediating ligand-induced platelet activation during primary hemostasis, GPIbα plays a role in thrombosis, thrombocytopenia, inflammation, and other disease states. Nurden et al., Inherited platelet disorders, Haemophilia, 2012, 18(Sup 4): 154-60 and Clemetson & Clemetson, Platelet GPIb complex as a target for anti-thrombotic drug development, Thromb Haemost, 2008, 99: 473-9. GPIbα is continuously proteolyzed in circulating platelets, with its extracellular domain, also known as glycocalicin, released into the plasma. This process is referred to as ectodomain shedding. GPIbα shedding is thought to be an indicator of damaged platelets. GPIbα shedding in platelets can be further stimulated by chemical or physiological agonists, such as Athrombin™, N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W7, a calmodulin inhibitor that sequesters calmodulin from binding to its ligands), carbonyl cyanide 3-chlorophenylhydrazone (CCCP, a drug that damages the mitochondria and induces apoptosis), and phorbol 12-myristate-13-acetate (PMA).
ADAM17 (A Disintegrin And Metalloprotease 17) is the physiological sheddase for GPIbα. Recombinant ADAM17 cleaves GPIbα based peptides at the Gly464-Val465 peptide bond, suggesting it to be the shedding cleavage site in GPIbα. ADAM17 has broad substrate specificity, and ADAM17 can recognize and cleave a substrate with an extended backbone conformation that is not strictly dependent on any particular side chain. ADAM17 has been shown to cleave physiologically GPIbα, tumor necrosis factor-alpha, and many other substrates with little sequence similarity including Glycoprotein V (GPV).
Broad-spectrum metalloproteinase inhibitors, such as hydroxamic acid-based GM6001 that chelates the zinc ion required for the metalloproteinase activity, strongly inhibit agent induced GPIbα shedding. Gardiner et al. report controlled shedding of platelet glycoprotein (GP)VI and GPIb-IX-V by ADAM family metalloproteinases. J Thromb Haemost, 2007; 5: 1530-7.    Bergmeier et al., report metalloproteinase inhibitors improve the recovery and hemostatic function of in vitro-aged or -injured mouse platelets. Blood, 2003, 102: 4229-35.    Gitz et al. report improved platelet survival after cold storage by prevention of glycoprotein Ibα clustering in lipid rafts. Haematologica, 2012, 97(12): 1873-1881.    Berndt et al. report ristocetin-dependent reconstitution of binding of von Willebrand factor to purified human platelet membrane glycoprotein Ib-IX complex. Biochemistry, 1988, 27: 633-40.    Takayama et al., report anti-platelet membrane glycoprotein VI monoclonal antibodies. See US. Patent Application Number 2011/0217318.    Wagner & Bergmeier report compounds for improving platelet recovery and functions. WO/2004/105837. See also U.S. Pat. No. 8,173,595, WO/2013/096932, WO/2011/162831, and US Patent Application 2013/0216513.    Mo et al. report transmembrane and trans-subunit regulation of ectodomain shedding of platelet glycoprotein Ib alpha. J Biol Chem, 2010, 285(42): 32096-32104.    Liang et al. report specific inhibition of ectodomain shedding of glycoprotein Ibα by targeting its juxtamembrane shedding cleavage site. J Thromb & Haemost, 2013, 11: 2155-2162.
References cited herein are not an admission of prior art.